1. Field of the Invention
The present invention relates to a technique of indirectly controlling a start time or an end time of a charge/discharge and a quantity of the charge/discharge so as to achieve a charge/discharge plan of an electric storage installation using a secondary battery connected to a wide-area power system, in particular, so as to improve an energy consumption performance and a social environmental performance as a whole power system in terms of a number of storage batteries freely connected in parallel and disconnected by end users.
2. Description of the Related Art
Electric power installations using storage batteries, that is, electric storage installations have been recently expected to come into wide use from an environmental point of view. For example, such electric power installations include an electric vehicle electrically driven by a storage battery and a motor and an electric plug-in hybrid car using a combination of a gasoline engine and an electric motor. If a charging of the electric power installations is conducted at midnight, the charging favorably contributes to the environment.
A number of large-capacity power installations including storage batteries are timer-controlled. Electric water heaters or natural refrigerant heat pump water heaters used in ordinary households typically conduct a heat storage operation in a prescribed time zone dependent on an electric rate system. Similarly, a start time of a charging of a power installation as described above can be timer-controlled.
Further, such a control system can be built based not only on a state of a single unit of the power installation but also on an optimization of customers' or users' power consumption as a whole. Japanese Laid-Open Patent Application, Publication No. 2004-364463 discloses a technique of managing a priority ranking among a plurality of electric power installations of a customer and controlling power consumption of all customers for its optimization as a whole.
The control system can be built based not only a range of individual customers but also on an overall power system including power feeding such as a large-scaled power generator. Japanese Laid-Open Patent Application, Publication No. 2004-364463 also discloses a technique of conducting a charging plan for each charging battery in an attempt to contribute to the environment as a whole society, in which information on a recommended charge time zone and charge quantity (for example, information on a discount of electric rates given if a customer uses less power in summer which is a demand season) is obtained from a means of controlling an overall power system.
Of the conventional techniques described above, the technique using a timer control has, however, a problem of having a difficulty in dealing with a future increase in the number of installations using storage batteries. In particular, a widespread use of electric vehicles means that fossil fuel-dependent vehicles are incorporated into an electric power system. It is thus expected that a structure of power demand drastically changes both widely and locally. The environmental performance from a viewpoint of a whole society has become more and more important. The conventional technique using a timer control has a limitation in that optimization of the whole power installations is attempted by changing timer-controlled parameters via off-line operations on a case-by-case basis.
If an online-controlled optimization of the whole power installations is performed, a state of not a limited range of the power system but the whole power system is required to be reflected to the optimization in order to efficiently improve the environmental performance of the whole society. As disclosed in Japanese Laid-Open Patent Application, Publication No. 2004-364463, a charging plan for each charging battery should be created at least according to the information on a recommended charge time zone and charge quantity which is provided from a viewpoint of the whole power system.
Meanwhile, however, to encourage customers to participate in a charge/discharge management program for the purpose of increasing a social benefit, it is required that each of the customers can enjoy a merit according to his/her participation in the program.
Japanese Laid-Open Patent Application, Publication No. 2004-364463 does not have a means of managing charge actions by type of charging, based on the recommended information. This means that a customer just pays for a total of a power consumption due to a charging plus that for ordinary use. The related art cannot create a mechanism in which, for example, a power quantity used for a charging is distinguished from others and is subject to receive an incentive as a specific social program regarding a charging management of electric vehicles.
Japanese Laid-Open Patent Application, Publication No. 2004-364463 is required to send information on a charging request to an external facility in advance of an actual charge action if the recommended information is subject to be updated on a daily basis or the like. In reality, however, a user does not always conduct a charge/discharge action as originally planned because of an accidental event or the like. It is therefore difficult that all of the users send all of their charging requests to the external facility without fail.
Any of the related arts described above have a difficulty in offering a social program for leading a customer to a desired charge/discharge action. A customer will not participate in the mechanism of managing his/her charge action if the customer suffers inconvenience in conducting his/her charge/discharge action from the mechanism. For example, if a user is scheduled to drive an electric vehicle at a given time, a charging should be completed by the time of departure. Otherwise, such a charging gives inconvenience to the user. There is a need of a charging plan which satisfies a restriction condition for a user's power installation usage and suboptimally complies with the recommended information for the whole power system. Moreover, to achieve a wide spread of the social program, it is necessary to create a mechanism in which a customer can receive a reasonable amount of incentive for such a suboptimal charge action.
In light of the problems described above, the present invention has been made in an attempt to improve an energy consumption performance and a social environmental performance of a power system as a whole based on actions taken by customers of the power system.